Temperature Control System In A Refrigeration Appliance

ABSTRACT

A temperature control system in a refrigeration appliance comprising: a cabinet defining at least one refrigerating compartment closed by a door; a compressor; and a control means provided with a timer and which is constructed to activate and deactivate the compressor when the interior of the refrigerating compartment reaches activation and deactivation temperatures, respectively. The control system comprises an ambient temperature sensor and an open door sensor which are operatively connected to the control means, the latter being designed to adjust the activation and deactivation temperatures of the compressor as a function of the ambient temperature external to the cabinet and the opening pattern of the door, in order to minimize the temperature variations of the food stored in the refrigerating compartment.

FIELD OF THE INVENTION

The present invention refers to a system for providing the automatic control of the operational temperature in a refrigeration appliance of the type which comprises a cabinet defining at least one refrigerating compartment closed by a door, a compressor, and a control means to activate and deactivate the compressor as a function of the temperature reigning in the interior of the refrigerating compartment.

PRIOR ART

The present invention is applicable to the domestic refrigeration appliances defined by a refrigerator or a freezer, in which the refrigerating compartment, as generically denominated herein, has a respective setting device, generally in the form of a knob, which allows the user to modify the operational conditions of the appliance, altering the activation and deactivation temperatures of the compressor to cooler or less cool values, from a medium nominal operational value.

In these known temperature control systems, when the user wants to select a lower food storage temperature he/she manually operates the setting device so that the control means detects the alteration in said setting and varies, correspondingly, the deactivation temperature of the compressor. It should be understood that the variation of the activation temperature of the compressor could also be altered or maintained constant in the case of the refrigerating compartments provided with a freezer function.

In these known systems, besides the fact that the user can adjust the operational temperature range within which the refrigeration appliance will work, by adjusting said range to cooler or less cool conditions, the control means is operatively associated with means to detect the current temperature in the refrigerating compartment and to verify whether it is in the same level or above the activation temperature of the compressor, when the latter is then activated. When the temperature of the refrigerating compartment informed to the control means is equal or inferior to the deactivation temperature of the compressor, the control means provides the deactivation of the latter. Such operational procedure makes the temperature within the refrigerating compartment to oscillate between the activation and deactivation temperatures of the compressor.

It is known from the art that the storage temperature inside the refrigerating compartment of either a refrigerator or a freezer, should be maintained as constant as possible during the whole storage period. For some food products, even a small temperature variation can bring serious consequences. Moreover, temperature fluctuations often cause condensation of the humidity on the stored products, which is undesirable as it can propitiate growth of microorganisms.

While the known control systems keep the refrigerating compartment automatically operating within the range of the activation and deactivation operational temperatures of the compressor, and allow the user to make manual adjustments to better suit the operational temperature range to the desired working conditions of the appliance, it should be noted that throughout the year significant ambient temperature variations can occur which are not perceived by the user and which can lead the refrigeration appliance to work in temperatures which are inadequately high for the correct and desired food storage, or in unnecessary low temperatures which also impair food storage and leads to higher energy consumption.

Such variations in the weather or in the ambient temperature require the user to adjust the setting device accordingly, so that the latter leads the control means to operate the refrigeration appliance in cooler or less cool conditions, as a function of the time of the year in which the appliance is working.

While the user can manually set the activation and deactivation temperatures of the compressor so as to better adjust the internal temperature of the refrigerating compartment to the ambient conditions reigning in a determined time of the year, such operation requires attention from the user, who must effectively participate to produce this setting of the operational temperature conditions of the refrigeration appliance.

Another aspect which is considered prejudicial to keep an adequate temperature inside the refrigerating compartment is the door opening pattern of said compartment. Thus, besides weather variations, the usage pattern the consumer applies to the refrigeration appliance is also a relevant parameter to adjust the positioning of the setting device. In relation to the usage pattern of the refrigerating compartment, i.e., the door opening pattern, the known systems do not allow the user to interfere voluntarily and selectively in the control means in order to modify the operational conditions of the refrigeration appliance, these operational conditions being maintained during the automatic operation of the compressor, according to the activation and deactivation temperatures that are set by the user in the setting device.

SUMMARY OF THE INVENTION

As a function of the disadvantages mentioned above, in which the user himself must make the settings in the setting device, aiming at avoiding the undesired oscillation in the food storage temperature during the operation of the refrigeration appliance, it is an object of the present invention to provide a temperature control system to be used in a refrigeration appliance of the type considered herein, which allows obtaining an automatic adjustment of the operational temperature inside the refrigerating compartment as a function of the variations in the ambient temperature in which the appliance is installed and also as a function of the door opening pattern the user applies to the refrigeration appliance.

This and other objects and advantages of the invention are attained by the provision of a temperature control system for a refrigeration appliance of the type which comprises a cabinet defining at least one refrigerating compartment closed by a door; a compressor; and a control means to activate and deactivate a compressor when the interior of the refrigerating compartment reaches activation and deactivation temperatures, respectively.

According to the invention, the control system comprises an ambient temperature sensor and an open door sensor which are operatively connected to the control means designed to adjust the activation and deactivation temperatures of the compressor as a function of the ambient temperature external to the cabinet and the door opening pattern, in order to minimize the temperature variations of the food stored in the refrigerating compartment of the refrigeration appliance.

The construction mentioned above allows the control means to periodically and automatically adjust the activation and deactivation temperatures of the compressor when the ambient temperature sensor and the open door sensor detect, respectively, the simultaneous occurrence of an ambient temperature deviation out of a predetermined range of acceptable operational temperatures and a deviation out of the door opening pattern in relation to a predetermined pattern within a certain time period.

With the constructive arrangement proposed herein, if the ambient temperature drops below a certain value and the user produces a low usage pattern of the appliance, i.e., a usage which corresponds to a reduced open door time in a certain period, the control means will adjust the activation and deactivation temperatures of the compressor to a less cool condition.

However, if the ambient temperature drops below a predetermined value and the user maintains a door opening pattern which is reasonable or within a predetermined pattern, the control means will keep the refrigeration appliance working in a condition corresponding to a default position defined by the electronic control, within an adjusting range available to the user in the setting device.

Similarly, if the ambient temperature rises beyond a certain predetermined value and if the door opening pattern is higher than the predetermined pattern, the control means will provide the automatic setting of the activation and deactivation temperatures of the compressor for the refrigerating compartment to operate in a cooler condition. However, if only the ambient temperature rises above the predetermined ambient value and the door opening pattern is maintained within the predetermined pattern, the control means will keep the compressor working in the condition corresponding to the default position of the manual adjusting range of activation and deactivation temperatures of the compressor that are available to the user.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below, with reference to the enclosed drawings given by way of example of a possible way of carrying out the invention, and in which:

FIG. 1 is a schematic median vertical sectional view of a refrigeration appliance with the present temperature control system; and

FIG. 2 is a schematic diagram illustrating the operating steps of the control means in the different operational conditions.

DETAILED DESCRIPTION OF THE INVENTION

As it can be noted from the enclosed drawings, the invention is directed to a temperature control system for a refrigeration appliance of the type which comprises a cabinet 10 defining at least one refrigerating compartment RC closed by a generally front door 11. The refrigeration appliance further comprises a refrigerating circuit which is illustrated only by the part defined by a compressor 20 operatively associated with a control means 30 provided with a timer 31 and which is constructed in any known adequate manner to activate and deactivate the compressor 20 when the interior of the refrigerating compartment RC reaches activation and deactivation temperatures which are respectively detected by a temperature sensor 40 positioned inside the refrigerating compartment RC so as to sense the air temperature reigning inside the latter. The temperature sensor 40 is also operatively associated with the control means 30 to inform the latter when the air temperature inside the refrigerating compartment RC reaches any of the activation and deactivation values of the compressor 20, said activation and deactivation temperatures being determined in different operational ranges of the refrigeration appliance according to a scale containing different operational temperature ranges which are associated with the different operational conditions of the refrigeration appliance.

It should be understood herein that the refrigeration appliance could be of the type comprising two or more refrigerating compartments RC, one defining for example a refrigerating compartment and the other a freezing compartment, which are designed to operate through independent controls operatively associated with respective air temperature sensors inside the compartment.

According to the invention, the temperature control system comprises an ambient temperature sensor 50 and an open door sensor 60 which are operatively connected to the control means 30 to continuously inform the latter about the ambient temperature of the installation place of the refrigeration appliance and about the opening pattern of the door 11 of the refrigerating compartment RC.

The constructive arrangement cited above allows the ambient temperature sensor 50 to continuously inform the control means 30 of the ambient temperature external to the refrigeration appliance, while the open door sensor 60 continuously informs the control means 30 of the summation of the times in which the door 11 remains open in a determined time interval, after which the control means 30 verifies whether the ambient temperature is below, within or above an acceptable and predetermined operational temperature range, and whether the summation of the times during which the door 11 remained open in said time interval is within a certain predetermined time pattern.

According to a constructive form of the invention, the time periods in which the control means 30 verifies the ambient temperature and the door opening pattern through the ambient temperature sensor 50 and the open door sensor 60 respectively, vary according to the design of the control system, being of about 30 minutes, for example. Thus, at each temperature setting time period, the control means 30 verifies whether it is necessary to adjust the activation and deactivation temperatures of the compressor 20 as a function of the ambient temperature external to the cabinet 10 and of the usage pattern of the door 11 within the time interval immediately before, said temperature setting being accomplished, if necessary, automatically without the user having to verify voluntarily said ambient temperature and door opening pattern parameters to manually adjust an usual operational temperature setting device available in a refrigerating compartment RC of said appliances.

The ambient temperature sensor 50 can be constructed in any adequate form known in the art, and the open door sensor 60 that can also be constructed in different forms, as long as it indicates to the control means 30 the occurrence of the opening and closing operations of the door 11 so that the control means 30, aided by the timer 31, can count the time periods in which the door remained open during each temperature setting time interval of the refrigeration appliance. The open door sensor 60 can have for example, the form of a switch activated by the door 11 itself.

According to the present temperature control system, the control means 30 is constructed to maintain the refrigeration appliance operating within a range of activation and deactivation temperatures of the compressor corresponding to an intermediate operational range within a range of activation and deactivation temperatures of the compressor which are previously determined during project of the appliance. Thus, if at the end of each time interval in which the door opening pattern and the ambient temperature, a situation is verified in which there is not the simultaneous occurrence of an ambient temperature deviation in relation to a predetermined range of acceptable operational temperatures and of a door opening pattern deviation in relation to a predetermined pattern, the control means 30 will not effect any alteration in the activation or deactivation temperatures ranges of the compressor 20, even though these parameters present a deviation in relation to the nominal values that are acceptable and considered adequate so that the compressor continues to operate with the activation and deactivation temperatures corresponding to the intermediary range of activation and deactivation temperatures of the scale of operational temperatures of the refrigeration appliance.

Upon occurring a simultaneous deviation out of the ambient temperature and door opening pattern parameters, the control means 30 will provide a respective adjustment of the activation and deactivation temperatures of the compressor 20 to an immediately subsequent temperature range above or below said scale of activation and deactivation temperature ranges of the compressor 20 previously determined during project of the refrigeration appliance.

It should be understood that the automatic temperature control system object of this invention could be constructed in two forms. In the first form, the activation and deactivation of the function are accomplished through a push button, for example located close to a user's interface 70 provided in an adequate location in the refrigeration appliance, generally in the external front region of the latter, as schematically illustrated in FIG. 1.

Thus, the user determines whether to use or not the function.

In the second form, the activation and deactivation of the function are inherent to the control means 30, and in this case the user does not produce any action to activate this function.

FIG. 2 illustrates the procedures or operating steps of the control means 30 during the operation of the appliance as a function of the parameters received from the ambient temperature sensor 50 and from the open door sensor 60 to execute, when required, an adjustment in the activation and deactivation temperatures of the compressor 20.

In the block diagram of FIG. 2, the references in alphabetic characters are those reproduced below with the respective meanings:

Time_Counter=Elapsed time counter (timer)

Open_Door_Time=Accumulated open door time in the period

t_(p)=Time period defined to automatically set the temperature ranges

t_(l)=Accumulated open door time which defines the low and high usage pattern of the refrigeration appliance

T₁=Low ambient temperature pattern

T₂=High ambient temperature pattern

RC_(a) and FC_(a)=Pattern temperature settings for the refrigerating and freezing compartments (warmer than the default value)

RC_(b) and FC_(b)=Pattern temperature settings for the refrigerating and freezing compartments (cooler than the default value)

As illustrated, the present control system is started from conditions of the control means 30 which are set to adjust the temperatures of both the refrigerating compartment RC and the freezing compartment FC (if existent) to the respective default values, the timer 31 being adjusted to zero and the summation of the open door accumulated time in the temperature setting time interval being also zeroed.

From the parameters above, the control means 30 verifies whether the door 11 of any of the compartments is open. If door 11 is open, the control means 30, by means of the timer 31, sums up the time periods in which the door 11 remains open, using this information to verify whether the open door accumulated time is higher than or equal to the time period TP defined for the automatic adjustment of the temperature ranges. In case this relation does not occur, the control means 30 returns the system to the step of checking the opening condition of any of the doors 11. In case a situation occurs in which the open door accumulated time is superior to the time period TP defined for adjustment, the control means 30 checks whether the ambient temperature is lower than or equal to the lower ambient temperature pattern and also whether the open door accumulated time is lower than the open door accumulated time which defines the low and high usage patterns of the product.

In case the conditions described above are checked by the control means 30, the latter promotes the adjustment of the temperature of the refrigerating compartment to a temperature pattern which is warmer than the default temperature, returning the system to the start, so as to accomplish a new verification at the end of a new predetermined time interval. On the other hand, in case the relations of ambient temperature are inferior or equal to the lower ambient temperature pattern and of open door accumulated time in the predetermined time interval being not lower than the door opening pattern time, the control means 30 will check whether the ambient temperature is superior or equal to the higher ambient temperature pattern, and whether the open door accumulated time is higher than the open door time pattern. In case this new operational situation occurs, the control means 30 adjusts the temperature of the refrigerating compartment under control to a temperature value cooler than the default temperature, returning the system to the start of the checking process so as to effect a new checking at the end of said predetermined time interval. In case said conditions do not occur, the control means 30 will keep the temperature of the refrigerating compartment in the default value, returning the control system to the start in order to accomplish a new verification at the end of a new setting time interval predetermined during project.

While only one form of carrying out the invention has been illustrated herein, it should be understood that changes could be made in the different component parts without departing from the inventive concept defined in the claims that accompany the present specification. 

1. A temperature control system in a refrigeration appliance of the type which comprises: a cabinet defining at least one refrigerating compartment closed by a door; a compressor; and a control means provided with a timer and constructed to activate and deactivate the compressor when the interior of the refrigerating compartment reaches, respectively, activation and deactivation temperatures, wherein it comprises an ambient temperature sensor and an open door sensor which are operatively connected to the control means, the latter being designed to adjust the activation and deactivation temperatures of the compressor as a function of the ambient temperature external to the cabinet and the opening pattern of the door in order to minimize the temperature variations of the food stored in the refrigerating compartment.
 2. The temperature control system as set forth in claim 1, wherein the control means is designed to periodically adjust the activation and deactivation temperatures of the compressor when the ambient temperature sensor and the open door sensor indicate, respectively, the simultaneous occurrence of an ambient temperature deviation out of a predetermined range of acceptable operational temperatures and a deviation out of the door opening pattern in relation to a predetermined pattern within a certain time interval.
 3. The temperature control system as set forth in claim 2, wherein the control means is constructed to periodically adjust the activation and deactivation temperatures of the compressor in predetermined time intervals.
 4. The temperature control system as set forth in claim 2, wherein the periodical adjustment of the activation and deactivation temperatures of the compressor, when instructed by the control means, provokes an alteration of the temperatures from an operational range to a range in a scale of activation and deactivation temperature ranges of the compressor.
 5. The temperature control system as set forth in claim 2, wherein the door opening pattern is defined by the summation of the times in which the door remained open within said time interval.
 6. The temperature control system as set forth in claim 1, wherein the open door sensor is defined by an electromechanical, electronic or magnetic switch.
 7. The temperature control system as set forth in claim 1, further comprising an interface which is selectively activated by the user to provide any of the activation and deactivation commands of said automatic temperature control system. 